Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
The crystal structure of low cristobalite (SiO2) was refined at 10, 293, and 473 K from time-of-flight neutron powder diffraction data. One of the Si-O distances and one Si-O-Si angle change considerably: 10 K, 1.602(1) and 1.617(1) Å, 144.7(1)°; 473 K, 1.605(2) and 1.590(2) Å, 148.4(1)°. The angular distortion of the…
Luminescence yields and decay lifetimes were measured on some metalloporphyrins including the complexes of the IIIb metal group. The S2 emission was observed for AlClTPP (TPP: tetraphenylporphin), GaClTPP, and InClTPP as well as some other TPP metal complexes, ZnP (P:porphin) and H4P2+ (diacid), while it was not detec…
Ion-beam sputter deposition of tantalum oxide films was investigated for possible optical coating applications. Optical properties of such films were found to be a sensitive function of oxygen-to-argon ratio in the ion beam. Refractive index and absorption coefficient were determined in the 250–2000-nm wavelength rang…
Any arbitrary generalized gradient-index interference coating (including homogeneous and inhomogeneous layers) possesses a digital configuration (sequence of thin high- or low-index layers), which is spectrally equivalent at all wavelengths. Such digital configurations are found directly from arbitrary-index profiles…
The ${\mathrm{Ni}}_{80}$${\mathrm{P}}_{20}$ alloy system has been investigated in both liquid and amorphous solid forms using molecular-dynamics computer simulation. Atomic interactions were modeled by central pair potentials selected to represent roughly the atomic sizes and relative bond strengths. Self-diffusion co…
The feasibility of producing erbium-doped silicon light-emitting diodes by molecular beam epitaxy is demonstrated. The p-n junctions are formed by growing an erbium-doped p-type epitaxial silicon layer on an n-type silicon substrate. When the diodes are biased in the forward direction at 77 K they show an intense shar…
The depolarised Rayleigh scattering temperature dependence of the seventh, eighth, ninth and tenth homologues of 4,n-alkyloxybenzoic acid was investigated. A sharp increase of the scattered light intensity upon cooling was observed in the middle of the nematic phase. Polarised microscopic investigations confirmed the…
Single crystal E.P.R. spectra of Fe(III) doped in hexaimidazole zinc(II) dichloride tetrahydrate have been investigated. The spectra are characteristic of Fe(III) occupying a substitutional zinc site and where it is under the influence of a strong tetragonal crystal field from the six imidazole ring nitrogens: superpo…
A high-pressure X-ray scattering study has revealed that the compressible molecular crystal SnI 4 gradually transforms from the crystalline to the amorphous state, this process being accompanied by a remarkable decrease in electrical resistivity induced by the pressure. Taken together with the Raman scattering study d…
The electronic band structure of black phosphorus has been studied by angle-resolved ultraviolet photoelectron (ARUPS). The experimental valence band structure has been successfully obtained by the use of the He I and Ne I resonance lines. The binding energies of some special points with almost no interlayer energy di…
Coherent inelastic neutron scattering provides detailed information about the correlated atomic displacements in the vibrational modes of a glass. As an example, we show the wave-vector dependence of the scattering function of vitreous Si${\mathrm{O}}_{2}$ corresponding to different peaks in the one-phonon density of…
A procedure for preparing titanium alloys is described. The procedure includes activation in a solution of chromic and hydrofluoric acids and perferentially dissolves the baser phase of the titanium alloys. Titanium alloys can then be plated, obtaining good adhesion. Adhesion ranges from 70-120 N/mm2. Only during chro…
Procedures for recording the proportion of coarse fibers in greasy wool sale lots were compared. The percentage of fibers greater than 1.5 times the mean provided an estimate of the coarse edge that was precise and not particularly sensitive to outliers; however, due to the high multiple correlation of this statistic…
The effects of amides and detergents on collagen to gelatin transition have been studied at neutral pH. Simple amides denature the protein. The substitution of H-atoms by the alkyl groups at the nonpolar end of amide increases the effectiveness of the compounds in destabilizing the collagen structure whereas substitut…
<div class="htmlview paragraph">Part of the break-in facilities of a heavy-duty engine production plant were equipped with ceramic monolith trap oxidizers, most of which were catalyst-coated. Non-carbon particulates from the combustion of diesel fuel and lubricating oil as well as dust and wear particles from th…
Carbon electrodes from cells were studied by electron spin resonance after various stages of discharge. Different behavior was observed in the temperature‐dependent part of the ESR linewidth, defined as "intrinsic linewidth," , when two different electrolytes were used. With one electrolyte, , the value stayed constan…
<div class="htmlview paragraph">HOT-DIP galvanized steel sheets have been increasingly used in the automotive industry. However, two major problems occur during spot-welding because of the presence of zinc: <ol class="list nostyle"> <li class="list-item"><span class="li-label">1/</span> &…
The fluorescence spectra of colonies of Propionibacterium acnes were studied under various experimental conditions. The spectra contained peaks at 580 nm and 620 nm. These bands were due to two different components; the 580 nm component was likely to be a metalloporphyrin, and there are indications that the 620 nm com…
Effects of hydrogenation and thermal processes on vibrational spectra and electrical conductivity of trans-poly-acetylenes have been examined on the basis of new assignments of IR and Raman bands. Enrichment of long conjugated segments and their proper packing are indispensable for high electrical quality.
Abstract Bei der Umsetzung von Oberflächen‐ Chrom (VI)/Silicagel mit Aluminiumalkylen — einer Reaktion, die zu den sogenannten „Phillips‐Kontakten der zweiten Generation”︁führt — wird das Metall i zwei 2e‐Schritten über eine isolierbare Chrom(IV)‐Zwischenstufe zu Cr I reduziert. Das Ausmaß der Reduktion ist vom Verhäl…